Process for dyeing acrylonitrilecontaining textile articles



United States Patent PROCESS FOR DYEING ACRYLONITRILE- CONTAINING TEXTILE ARTICLES William W. Rankin, Charleston, W. Va., assignor to Union Carbide and Carbon Corporation, a corporation of New York No Drawing. Application August 23, 1952, Serial No. 306,058

14 Claims. (Cl. 8-55) This invention relates to the dyeing of textile articles formed from or containing filaments and fibers made of acrylonitrile-containing polymers. It has especial utility for the dyeing of articles formed from polyacrylonitriles and from copolymers of acrylonitrile with a wide range of other polymerizable unsaturated compounds containing an olefinic double bond, such as vinyl chloride, vinyl acetate, methyl methacrylate, 2-vinylpyridine, acrylamide, alpha-methacrylamide, and mixtures of such polymers and/or copolymers.

In recent years important advances have been made in the art of dyeing articles made from dye-resistant acrylonitrile-containing resinous polymers by a novel and commercially practicable process wherein textiles and other articles made from such polymers and from mixtures thereof are treated with an aqueous solution containing a small amount of a compound yielding cuprous ions. This so-called copper technique of dyestutf application is believed to represent the first commercially practicable method for dyeing articles made from acrylonitrilecontaining resinous polymers to deep shades with acidtype, direct-type and water-soluble acetate-type dyestuffs.

Prior to the present invention the copper-dyeing technique could not safely be applied to the dyeing of these articles with the well-known class of water-dispersible acetate-type dyestuffs which often possess outstanding light-fastness. This appearsto be due to a chemical reaction between the dyestuif and the copper compound which precipitates in the dyebath a scum which appears to be a complex of the dyestuit and copper. Articles dyed in such a bath have an extremely muddy, unsatisfactory appearance. Under some conditions the scum may block penetration by the dye liquor so that portions of the article remain more or less undyed. Consequently, it has not been practical to employ the advantageous copperdyeing technique for dyeing such articles with the Watersoluble dyestuffs of the aforesaid types where, concurrently therewith or subsequently thereto, a dyeing with a waterdispersible acetate-type dyestuff was desired.

The present invention is based in important part on applicants discovery that textile and other articles made from the aforesaid resinous acrylonitrile-containing polymers and copolymers eifectively can be dyed using dyebaths containing one or more water-soluble dyestuffs of the class of acid-type, direct-type and water-soluble acetate-type dyestuffs in conjunction with one or more waterdispersible acetate-type dyestuffs by proceeding in the manner herein described. This is an important discovery in view of the known difiiculties encountered in attempts to use the well-known Water-dispersible acetate-type dyestuffs in dyebaths containing copper compounds.

The use of mixtures of the water-dispersible acetatetype dyestuffs with water-soluble dyestuffs of the types herein described provides important advantages in dyeing articles made from acrylonitrile-containing polymers since theforrner have excellent leveling qualities and good wash-fastness and, with proper selection of the dyestufi,

provide a dye formula of excellent light-fastness. Acidtype dyes applied by the present process have outstanding wash-fastness and lightfastness, these properties varying with the dyes selected. Usually, less dyestuifs is required for heavy color shades with the acid-type dyes than with the water-dispersible acetate-type dyes. Pastel shades are simple to obtain and do not require dye assistants. Mixtures of acid-type and water-dispersible acetate-type dyestuifs applied by the present process are particularly efiective where heavy shades with excellent wash-fastness and light-fastness are required.

Among the more important objects of the invention are the following: to provide in novel manner for the dyeing of textiles and other articles made from resinous acrylonitrile-containing polymers with one or more water-dispersiole acetate-type dyestuffs in admixture with one or more water-soluble dyestuffs of the acid-type, direct-type and/ or water-soluble acetate-type; to provide, in the dyeing of such articles with mixtures of these Water-soluble and water-dispersible dyestulfs by a form of modified copper technique, for controlling the exhaustion of the dyestulf and improving the appearance and shade of the dyed article while minimizing the amounts of dyestuffs and copper compound required to yield a dyed article of a desired color shade; and to provide, in the dyeing of such articles by a process involving the use of a cuprous compound, for making available in the dyebath in active available form only approximately the amount of copper compound required to impart the desired color shade to the article being dyed.

According to one modification of the present invention, a textile or other article made from or containing a resinous acrylonitrile-containing polymer of the aforesaid ture of one or more water-dispersible acetate-type dyestuffs together with. one or more water-soluble dyestuffs of the class consisting of acid-type, direct-type and Watersoluble acetate-type dyestuffs. T he dyebath also may contain, when desired, a dispersing and leveling agent, and/or a swelling and penetrating agent for the resin. The dyebath then is slowly raised to a temperature of at least F. and preferably to a boil, and dyeing at such temperature is contained for a time suflicient to fix the waterdispersible acetate-type dyestuffs in the fibers. This commonly requires around 30 minutes or more. Concentrated sulfuric acid or the equivalent then is added as needed to bring the pH of the dyebath within the range between 2.0 and 7.0, and preferably around 6, and heating is continued at temperatures within the range from around 175 F. to around the boiling point of the bath or higher for a brief period, usually around 15 minutes. Then while maintaining the temperature within that range there is slowly added to the dyebath, preferably dropwise, over a period of 10 to 15 minutes or more, small successive amounts of a solution of a cuprous compound, or of an aqueous liquid containing a cupric compound and sufficient of a dilute aqueous solution of a reducing agent for that compound to produce cuprous ions in the solution at a slow rate, while minimizing the further conversion of such ions to forms of copper ineifective in the process. The dyeing then is continued at temperatures around 175 F. or above, and preferably at the boiling point of the dyebath, until the desired shade of color is achieved in the article, or until the dye .is exhausted.

Additional dyestuff can be added to the bath if and as desired, since there is never present therein such an excess of cuprous ions as to precipitate the dye prematurely. Usually, for best results, the dyeing is continued, after the addition of the copper compound has been oompleted, for a total of at least 30 minutes at the dyeing temperature.

The amount of cuprous compound or the equivalent employed depends in considerable degree upon the depth of color desired. Full uniform color shades are commonly secured using dyebaths containing 0.8% and less of the cuprous ions, while for light shades the bath may contain as little as 0.04% of the cuprous ions.

By adding the liquid containing cuprous ions to the dyebath in small successive increments, not only are remarkably uniform and scum-free dyeings obtained but in many cases substantially less dyestuff is required to obtain color shades equal in depth to those obtained when the liquid containing cuprous ion-s was added en masse to the bath prior to the dyestuff; and excess copper which might impair the light-fastness of the dyed article is avoided. Moreover, a high degree of control is se cured over the final shade or depth of color of the dyed article not heretofore obtainable, thus permitting exceedingly close shade matches.

In the interest of securing optimum color values, lightfastness, etc, it is preferred to use the cupric compound and the reducing agent in the weight ratios of 120.4 in closed systems, and in the ratios of 1:0.6 in open systems where the article being dyed may be exposed for a considerable time to the open air.

If desired, delustering of the article in the dyebath is minimized by the addition to the dyebath of around 40% to 200% or more of an alkali metal sulfate, based on the weight of the article, at any stage of the dyeing operationnote Examples 1 and 5-and particularly after the addition of the cuprous compound has been completed. The dyed article then is scoured in Well-known manner at around 140 F. in a dilute solution containing a detergent. is rinsed with water, and then is air dried at temperatures commonly around 160 F. If necessary, the dyed article may be further relustered 'by heating the 'dry article at 240 F. to 250 F. with dry heat for a brief period.

A wide range of swelling or penetrating agents for the resin of the article effectively can be used in the dyebath when desired. Particularly effective are derivatives of diphenyl and of benzlphenyl containing one or more hydroxy groups attached to a carbon atom or atoms of an aromatic ring orrings. Such compounds also can contain one to two chlorine atoms attached to a carbon atom or atoms of the same or different aromatic rings. Among suitable compounds are the o-, m, and pphenylphenols, the o,o-, o,p'-, and m,m-biphenols,

p-benzylphenol, p,p'dihydroxydip'henylmethane, and the p,p dihydroxydichlorodiphenylme-thanes. Such swelling agents, when used, can be added to the dyebath conveniently in the form of their alkali metal salts in alkaline solution prior to acidification of the bath. 'P-p'henyl- I phenol, a representative solvent assistant, is highly effective in proportions around 1% to of the dry weight of the article being dyed. When only medium or light shades of color are desired in the dyeings, a swelling agent for the resin fiber is not required, and ordinarily is not used.

It often is desirable to have present in the dyebath from 1% to 3% or more of a dispersing and leveling agent, preferably one of the cationic or of the anionic type. Highly efiective for the purpose are the water dispersible cationic products of the condensation of ethylene oxide with an organic amine. Such a product now is being marketed under the trade name, Peregal OK." Such products can be made by the process disclosed in United States Patent No. 2,214,352.

The liquid mixture containing cuprous ions employed in the process conveniently can be made by 'mixing, preferably at room temperature, a dilute aqueous solution of a cupric compound such as cupricsulfate, chloride, acetate or formate, containing a small amount, e. g., from 0.1% to 1.0% or more, of a reducing agent for the copper compound, both based upon the weight of the liquid mixture. Preferred reducing agents include the metal formaldehydesulfoxylates, such as the zinc and the alkali metal formaldehydesulfoxylates, hydroxylamine sulfate and dihydrazine sulfate. Glyoxal also is a useful reducing agent in the process. The solution of the reducing agent should be present in amount sufiicient to reduce at least the major portion of the cupric compound to the cuprous form. The treating mixture preferably is employed shortly after its preparation.

Should exhaustion of any of the dyestuffs occur at any stage of the dyeing operation, additional dyestuff can be added Without objectionable effect upon the dyed article, since at no stage in the present dyeing process is there present an injurious excess of the copper compound and/ or reducing agent.

The following examples serve to illustrate the invention. 1n the examples, and throughout the specification and claims, all parts are given in terms of weight and all percentages are based upon the dry weight of the article being dyed, unless otherwise specified. Each dyebath had a pH within the range from 2.0 to 7.0 during the dyeing in the presence of the cuprous compound.

EXAMPLE 1 A quantity of staple fiber spun from a resinous copolymer of acrylonitrile and vinyl chloride containing of acrylonitrile in the polymer and having a specific viscosity at 20 C. of about 0.26 was scoured in an aqueous solution of a detergent. it then was treated for about 10 minutes at room temperature in an aqueous bath containing 1% of sodium hexametaphosphate and 2% of a sodium alkyl aryl sulfonate being marketed under the trade name, Nacconol NR. The weight ratio of the bath to dry fiber was 15 to 1. To this bath then were added 6% of Anthraquinone Blue SWF 150%, a water-soluble acid-type dyestutf of Prototype No. 12; 4% ofEastman Fast Yellow 4RLF, and 2% of Eastone Fast Red GLF, the latter two being Water-dispersible acetate type dyestuffs. The temperature of the dyebath and contents Was raised slowly to a boil over a period of 15 minutes and dyeing at this temperature proceeded for 30 minutes. Then 0.5% of concentrated sulfuric acid was added to adjust the pH of the dyebath to around 6.0 After about 15 minutes there was slowly added dropwise to the boiling dyebath a mixture containing cuprous ions previously prepared by mixing at room temperature (about 70 F.) an aqueous solution containing 2% of cupric sulfate, based on the dry fiber weight, in times its weight of water, and an aqueous solution containing 0.8% of zinc formaldehydesulfoxylate, based on the fiber weight, in 50 times its weight of water.

After addition of this mixture was completed, the dyeing was continued at the boil for 30 minutes, following which 200% of anhydrous sodium sulfate was slowly added, and dyeing continued for another 30 minutes. The dyed fibers were scoured and then air dried at 160 F. for minutes. The fibers had an excellent, uniformly full navy blue shade which showed good washand crockfastness.

EXAMPLE 2 Five pounds of staple fibers of the kind recited in Example l were scoured and then treated at room temperature for 10 minutes in a stock dyeing machine of 5 pounds capacity with 15 times its dry weight of an aqueous bath containing 1% of sodium hexametaphosphate and 2% of Nacconol NR. The bath then was heated to F. and the following dyestuffs added: 6% of Anthraquinone Blue SWF an acid-type dyestuif; 4% of Eastman Fast Yellow 4 RLF; and 4% of Eastone Fast Red GLF, the last two being water-dispersible acetate-type dyestuffs. After heating the dyebath to 210 F. for 40 minutes to is in the fiber the water-dispersible dyestulf, 0.5% of concentrated sulfuric acid was added thereto. The dyeing was continued at the boiling point for minutes, after which there was slowly added dropwise a mixture containing cuprous ions, prepared in the manner described in Example 1. After continuing the dyeing at the boiling temperature'for another hour, 200% of anhydrous sulfate was added slowly and the dyeing continued for 30 minutes at the boil. The fiber then was scoured, and was dried at 248 F. for 15 minutes. The fibers were dyed to a uniformly full shade, and showed good wash-fastness and crock-fastness.

On the other hand, in another experiment conducted under the conditions described in Example 2, excepting that the aqueous mixture containing the cuprous ions was added rapidly in bulk to the aqueous dyebath containing the fibers and the mixture of dyestuffs after addition of the'sulfuric acid and while at 100 F., and thereafter the bath was heated to the boiling point, the fibers were not dyed to a full shade, and the cleanup of the dyestutf on the surface of the fibers was poor due to dyestuif precipitation.

EXAMPLE 3 Fifty pounds of staple fiber stock of the type described in Example 1 were placed in a Smith-Drum stock dyeing machine with water in a water to dry stock ratio of 15 to 1. Two per cent of Nacconol NR and 1% of sodium hexametaphosphate were added to the bath, followed by 6% of Anthraquinone Blue SWF 150%, 4% of Eastman Fast Yellow 4RLF, and 4% of Eastone Fast Red GLF inaqueous solutions. The dyebath was raised to 210 F. and held there for 30 minutes, at which time0.5% of concentrated sulfuric acid was added, and the dyeing continued for 15 minutes. An aqueous mixture containing cuprous ions, prepared in the manner described in Example 1, with the exception that the solutions of the copper compound and reducing agent were mixed at 120 F., then was added dropwise to the boiling bath during 15 minutes, and the dyeing was continued for another 30 minutes. Then 200% of sodium sulfate was added slowly. Dyeing at the boil was discontinued after another hour. A test portion of the dyed fiber was scoured and then dried at 248 F. for 15 minutes. The resultant stock was dyed level, and the cleanup of the dye at the surface of the fiber was excellent.

EXAMPLE 4 The dyebath and contents described in Example 3, re-

maining after removal of the test portion of fiber'mentioned in that example, were heated to 210 F., 1% of Eastman Fast Yellow 4RLF and 2% of Eastone Fast Red GLF were added thereto, and heatingcontinued for 30 minutes. Thereafter the color shade ofthe fiber again was deepened by the addition of. 1% of Anthraquinone Blue SWF 150%, followed by the slow addition during 15 minutes to the bath, maintained at 210 F., of a liquid containing cuprous ions, and prepared by mixing together an aqueous solution containing 0.25% of cupric sulfate and one containing 0.1% of zinc formaldehydesulfoxylate. The dyeing was continued for 30 minutes, after which, in order to deepen the color shade still further, there were added to the hot dyebath 1% of Anthraquinone Blue SWF 150% and 0.5% of Eastman Fast Yellow 4RLF. Fifteen minutes thereafter a mixture containing cuprous ions, freshly made by mixing an aqueous solution containing 0.15% of cupric sulfate with an aqueous solution containing 0.07 of zinc. formaldehydesulfoxylate, was added dropwise to the dyebath held at 210 F. until the desired shade was attained. An additional 200%, of sodiumsulfate, was added tothe dyebath to reluster the dyed fiber, and the heating continued for 30 minutes. The fiber then was scoured and dried as described in- Exvtype dye, Prototype 43.

6 ample 2. The fiber was dyed to a level and uniform midnight blue shade. The fiber was free from precipitated or unfixed dyestutf.

EXAMPLE 5 Spun yarn made from a commercially available polyacrylonitrile fiber being marketed under the trade name, Orlon, type 41, and said to contain over and up to of acrylonitrile in the polymer was first scoured and then placed in an aqueous bath at a bath to article weight ratio of 60 to 1. The bath containing 4% of Xylene Milling Blue GL (C. I. 833) an acid-type dye, and 4% of Celliton Fast Yellow GA, 9. water-dispersible acetate-type dye, Prototype 242, and 1% of Peregal OK. Then 40% of sodium sulfate was added to the bath and the temperature was raised to 208 F. and dyeing carried out for 30 minutes. The pH of the bath then was lowered to 5.0 with sulfuric acid. Thereafter, during 30 minutes there was added dropwise to the dyebath a liquid containing cuprous ions prepared at room temperature as a dilute aqueous solution containing 0.25% of cupric sulfate and 0.125% of zinc formaldehydesulfoxylate, both by weight of the treating liquid, to obtain dyebath exhaustion. An amount of reduced copper corresponding to 1.6% of cupric sulfate, based upon the dry weight of the yarn, was required to give to the yarn the optimum color values. The dyeing proceeded at a uniform rate to the desired shade.

EXAMPLE 6 EXAMPLE 7 Following the procedure described in Example 5, a quantity of staple fibers made from a copolymer of acrylonitrile and vinyl chloride having an acrylonitrile content of about 40% and a specific viscosity at 20 C. of about 0.26 was dyed uniformly to the desired green shade. In this case reduced copper ions corresponding to 1.2% of cupric sulfate, based upon the dry weight of the fibers, was required.

EMMPLE 8 Following the method described in Example 5, a quantity of continuous filament yarn known under the designation, X-S 1, and believed to be a coplymer of acrylonitrile with acrylamide, was readily dyed to a goodgreen shade. For optimum color value and ex haustion of the dyestufi, reduced copper corresponding to 0.6% of cupric sulfate, based upon the dry yarn Wei ht. qu re EXAMPLE 9 Staple fibers made from a resinous :copolymer #of acryonitr'ile and vinyl chloride containing about 40% of a .:rylonitrile in the polymer and having a specific viscosity at 20 C. of about 0.26, were scoured and placed in an aqueous bath at a bath to fiber ratio of about 60 to 1. The bath contained 1% of Peregal OK, 40% of sodium sulfate, 2% of Alizarine Direct Biue ARA, an acid dyestuff (Prototype ll),-and 4.0% of Artisil Direct Orange 2R Cone, a dispersed acetate The bath temperature was raised to 208 F. and dyeing carried out for 30 minutes. The pH of'the bath then was lowered to 5.0 with sulfuric acid. Thereafter there was slowly added dropwise to the dyebath, held at 208 F., aliquid containing cuprous ions prepared at room temperature as an aqueous solution containing 0.25 of cupric sulfate and 0.125% of hydroxylarnine sulfate, both based on the weight of the-said solution, until the desired'shade of olive green was secured. The dyeing proceeded smoothly. Cuprous compounds in amount corresponding to 2.6% of cupric sulfate, based upon the weight of the dry fibers, were required to obtain the desired olive green shade.

EXAMPLE Treating the staple fibers described in Example 9, and following the method described in that example, with the exception that the dyestuffs used were 2% of Anraquinone Blue RXO, an acid dye (C. I. 1076), and 4.0% of Celliton Fast Yellow GA, a dispersed acetate dye, Prototype 242, and the treating liquid was made at room temperature and consisted of an aqueous liquid containing 0.25% of cupric sulfate and as reducing agent 0.125% of dihydrazine sulfate, both based upon the weight of the treating liquid, the dyeing proceeded smoothly. To secure the desired shade of green color, 3.9% of cupric sulfate and 1.95% of dihydrazine sulfate, based upon the weight of the dry fiber, were required.

EXAMPLE 11 Treating the staple fibers described in Example 9, and following generally the procedure of that example, with the exception that the dyestuffs used were 2% of Anthraquinone Blue SWF 150% Conc., and 4% of Celliton Fast Yellow GA, and the dyebath also contained 10% of sodium p-phenylphenoxide as a penetrating agent, the pH of the bath was lowered to 6-7 before adding the dyestuffs. The fibers were added to this dyebath and the temperature raised to 175 F. and dyeing continued for 30 minutes. The pH of the bath then was lowered to a value of 4-5 with sulfuric acid and then there was added slowly dropwi'se thereto the liquid containing cuprous ions, :niade in the manner described in Example 5. The slow addition of the treating liquid was continued while heating at 175 F. until the desired color shade was secured. This required cuprous ions corresponding to 4.4% of cupric sulfate, based upon the dry weight of the fibers. The dyeing proceeded smoothly at all times.

Among the many dyestuffs useful in the process are the following:

Acid-type dyestuffs Trade name: Color Index No. Xylene Milling Blue BL 833 Vitrolan Orange R. Cone Pr. 146 Xylene Milling Yellow P Xylene Milling Yellow 2GP Xylene Fast Red 261 Xylene Light Rubine 2GS Calcoid Neutral Brown RS Anthralan Red BA-CF Pr.210

Chromaven Milling Orange G Cone 274 Alizarine Light Brown BL Alizarine Light Green GSN Alizarine Light Gray RLL Alizarine Light Red R Alizarine Sky Blue BSCF 1088 Alizarine Cyanine Green GHN-CF 1078 Brilliant Alizarine Light Red 4B Sufonine Red G 430 Calcochrome Alizarine Gray 2BLS Pr. 206 Xylene Fast Rubine 3GP B12412 Amacid Red 3B Conc 208 Sulfonine Orange GS Pr. 151 Sulfonine Yellow 2G 642 Cloth Red G 249 Croceine Scarlet MOO 252 Anthraquinone Violet R 1080 Anthraquinone Blue SWF 150% Pr. 12 SupramineYellow SGLA-CF Pr. 474 Calcocid Milling Red 3R Conc 275 Direct-type dyestufls Trade name; Color 'Index No. Calcomine Brilliant Yellow Cone 365 Fastusol Brown LBR Fastusol Red 4BA 278 Calcodur Yellow BLConc. 814 Calcodur Yellow NN 814 Water-soluble acetate-type dyestufis 1 This dyestutl has the structure:

Water-dispersible acetate-type dyestufls Trade name: Color Index No.

Artisil Direct Orange 2R Pr. 43 Amacel Brilliant Blue B Ex Pr. 228 Celliton Fast Yellow GA Pr. 242 'Celliton Fast Violet 6BA Pr. 241 Celliton FastRed GGA Ex. Conc. Pr. 236 Celliton Fast Rubine BA-CF Pr. 238

Eastman Fast Blue GLF Eastone Fast Red GLF 2 This dyestuif has the following structure:

This dyestuff has the following structure It will be understood that the dyeing can be conducted at temperatures above atmospheric in fluid-tight vats under pressure providing that the temperatureis substantially below the strain-release temperature of the resin article, e. g., 250 F. The strain-release temperature is that temperature at which internal strains locked within the article are released, with resultant objectionable change in the shape of the article.

Variations in the order of the procedure of adding to the dyebaththe various components, other than the copper-containing agent, can be made without departing from the invention. Also, the swelling agent, when used, can be added to thebath from a solution thereof in a suitable solvent, or it may be added in the form of a micronized powder.

It is important, for best results, that the dyeing with the water-dispersible acetate-type dyestuffs be begun and substantiallycompleted in the absence of a cuprouscompound and that, if it is found necessary or desirable to add additional quantities of such a dyestuif during the dyeing operation, the dyebath should be substantially depleted of the cuprous compound at the time of such addition thereto. On the other hand, the water-soluble dyestuffs herein described may be present at any or all stages of the dyeing operation.

The specific viscosit'ies of the resins referred to herein arse-.9 3:

9 were determinedat 20 C. using an Ostwald viscosimeter accordance with the formula: Specific viscosity= Viscosity of a solution of 0.1 gram of the resin in 50 cc. of solvent 1 Viscosity of the solvent In determining these specific viscosities, cyclohexanone was used with the resins of Examples 1 to 4, 7,and.9 to 11; and dimethylformamide was used with the resin of Example 6. The specific viscosity of the resin is a direct function of its average molecular weight.

The invention is susceptible of modification within the scope of the appended claims.

I claim:

1. Process for dyeing textile and other articles made from resinous polyacrylonitriles and copolymers of acrylonitrile with at least one other polymerizable compound containing a single olefinicdouble bond with a water-soluble dyestuflf and a water-dispersible dyestuff, which comprises treating such an article for at least minutes with an aqueous dyebath maintained at a temperature of from around 175 F. to a temperature near but substantially below the strain-release temperature 'of such article, said dyebath containing at least one waterdispersible acetate-type dystuif and at least one watersoluble dyestufi" selected from the class consisting of the acid-type, the direct-type and the water-soluble acetatetype dyestufis, thereafter adjusting the pH of the bath to between 2 and 7, and, While the dyebath is at a temperature within the said range, slowly adding thereto small successive amounts of an aqueous liquid containing cuprous ions until the article attains the desired shade of color.

2. Process for dyeing textile articles made from resinous polyacrylonitriles and copolymers of acrylonitrile with at least one other polymerizable compound containing a single olefinic double bond with a water-soluble dyestuflf and a water-dispersible dyestuif, which comprises treating such an article for at least 10 minutes with an aqueous dyebath maintained at a temperature between around 175 F. and about 250 F. and containing at least one water-dispersible acetate-type dyestufi and at least one water-soluble dyestufi selected from the class consisting of the acid-type, the direct-type and the watersoluble acetate-type dyestufis, thereafter adjusting the pH of the bath to between 2 and 7, and, while the dyebath is at a temperature within the said range, slowly adding thereto in small successive amounts a mixture of a dilute solution of a cupric compound and a dilute solution of a reducing agent for the latter in amount sufficient to form cuprous ions in the dyebath, and continuing the addition of the said mixture and the dyeing of the article .at the said temperature until the desired shade of color has been attained therein.

3. Process for dyeing textile articles made from resinous polyacrylonitriles and copolymers of acrylonitrile with at least one other polymerizable compound containing a single olefinic double bond with a water-soluble dyestufi and a water-dispersible dyestulf, which comprises treating such an article for at least 10 minutes with an aqueous dyebath maintained at a temperature between around 175 F. and about 250 F. and containing at least one water-dispersible acetate-type dyestuif and-at least one water-soluble dyestufir selected from the class consisting of the acid-type, the direct-type and the water-soluble acetate-type dyestuffs, thereafter adjusting the pH of the bath to between 2 and 7, and, while the dyebath is at a temperature within the saidrange, slowly adding thereto small successive amounts of a mixture containing a dilute solution of a cupric compound and of a reducing agent for the latter sufficient in amount to release in the dyebath at least 0.04% of cuprous ions, and continuing the addition to the dyebath of the said mixture and the heatingof the article at the said temperature until the desired shade of color has been attained therein.

i 4. Process as defined in claim 3'whe1'cin the reducing agent is ametal formaldehydesulfoxylate. 1

5. Process as defined in claim 1, together with a step of adding a water-soluble relustering agent to the dyebath prior to completionofthe high temperature dyeing operation.

6. Process as defined in claim 1 wherein the said'dyebath .also contains a swelling agent for the resinous material. s

v 7. Process for dyeing textile articles made from resinous polyacrylonitriles and copolymers of acrylonitrile with at least one other polymerizable compound containing a single olefinic double bond with a water-soluble dyestufi and a water-dispersible dyestutf, which comprises treating such an article for at least 10 minutes with an aqueous dyebath maintained at a temperature between around F. and about 250 F. and containing at least one water-dispersible acetate-type dyestuf'r and at least one water-soluble dyestufi selected from the class consisting of the acid-type, the direct-type and the watersoluble acetate-type dyestuffs, thereafter adjusting the pH of the bath to between 2 and 7, and, while the dyebath is at a temperature within the said range, slowly adding thereto in small successive amounts a mixture of a dilute solution of a cupric compound and a dilute solution of a reducing agent for the latter in amount sufficient to form cuprous ions in the dyebath, continuing the addition of the said mixture and the dyeing of the article at the said temperature until the desired shade of color has been attained therein and, at any time prior to completion of the dyeing, adding to the dyebath a supplemental amount of a watersoluble dyestuff of the aforesaid class thereof.

8. Process for dyeing textile articles made from resinous polyacrylonitriles and copolymers of acrylonitrile with at least one other polymerizable compound containing a single olefinic double bond with a water-soluble dyestufi and a water-dispersible dyestufi, which comprises treating such an article for at least 10 minutes with an aqueous dyebath maintained at a temperature between around 175 F. and about 250 F. and containing at least one water-dispersible acetate-type dyestuff and at least one water-soluble dyestuif selected from the class consisting of the acid-type, the direct-type and the water-soluble acetatetype dyestuffs, thereafter adjusting the pH of the bath to between 2 and 7, and, while the dyebath is at a temperature within the said range, slowly adding thereto in small successive amounts a mixture of a dilute solution of a cupric compound and a dilute solution of a reducing agent for the latter in amount suflicient to form cuprous ions in the dyebath, and continuing the addition of the said mixture and the dyeing of the article at the said temperature until the desired shade of color has been attained therein and, at any time prior to completion of the dyeing other than the time during which the mixture containing the copper compound is being added to the dyebath, introducing into the dyebath a supplemental amount of a water-dispersible acetate-type dyestuff.

9. Process as defined in claim 8 wherein the said reducing agent is a metal formaldehydesulfoxylate.

10. Process as defined in claim 8 wherein the said reducing agent is dihydrazine sulfate.

11. Process as defined in claim 8 wherein the said reducing agent is hydroxylamine sulfate.

12. Process as defined in claim 8 wherein the copper compound and the said reducing agent are used in the weight ratios within the range between 1:04 and 1:0.6.

13. Process for dyeing textile articles made from polyacrylonitriles and copolymers of acrylonitrile with at least one other polymerizable compound containing a single olefinic double bond with a mixture of Water-soluble and water-di spersible dyestuffs, which comprises treating such an article for at least 10 minutes with an aqueous dyebath maintained at a temperature between around 175 F. and its boiling point, and containing at least one water-dispersible acetate-type dyestutr and at least one water-soluble dyestutf selected from the class consisting-of-the acid type, the direct-type and the water-soluble acetate-type dyestuffs, thereafter adjusting the pH 'of the bath'to between 2 and 7, and, while the dyebath is=inaintained at ate'mperature within the said range, slowly adding thereto in small successive amounts an aqueous liquid containing cuprous ions until the desired shade of color has been attained.

14. Process as defined in claim 13 wherein a'sw'elli'ng agent for the resin article is added to the dyebath prior'to the addition thereof ofthe liquid containing cuprous ions. 10

References Cited in the file of this patent 

1. PROCESS FOR DYEING TEXTILE AND OTHER ARTICLES MADE FROM RESINOUS POLYACRYLONITRILES AND COPOLYMERS OF ACRYLONITRILE WITH AT LEAST ONE OTHER POLYMERIZABLE COMPOUND CONTANING A SINGLE OLEFINIC DOUBLE BOND WITH A WATER-SOLUBLE DYESTUFF AND A WATER-DISPERSIBLE DYESTUFF, WHICH COMPRISES TREATING SUCH AN ARTICLE FOR AT LEAST 10 MINUTES WITH AN AQUEOUS DYEBATH MAINTAINED AT A TEMPERATURE OF FROM AROUND 175* F. TO A TEMPERATURE NEAR BUT SUBSTANTIALLY BELOW THE STRAIN-RELAERSE TEMPERATURE OF SUCH ARTICLE, SAID DYEBATH CONTAINING AT LEAST ONE WATERDISPERSIBLE ACETATE-TYPE DYSTUFF AND AT LEAST ONE WATERSOLUBLE DYESTUFF SELECTED FROM THE CLASS CONSISTING OF THE ACID-TYPE, THE DIRECT-TYPE AND THE WATER-SOLUBLE ACETATETYPE DYESTUFFS, THEREAFTER ADJUSTING THE PH OF THE BATH TO BETWEEN 2 AND 7, AND, WHILE THE DYEBATH IS AT A TEMPARATURE WITHIN THE SAID RANGE, SLOWLY ADDING THERETO SMALL SUCCESSIVE AMOUNTS OF AN AQUEOUS LIQUID CONTAINING CUPROUS IONS UNTIL THEA ARTICLE ATTAINS THE DESIRED SHADE OF COLOR. 